There has been known a variable valve timing controller having a housing receiving a driving force from a crankshaft and a vane rotor in the housing transmitting the driving force to a camshaft, in related art. In related art, a valve operation timing is controlled by driving the vane rotor in the direction of a retard chamber or an advance chamber.
In related art, as shown in FIG. 11, a vane rotor 210 is fastened to a camshaft 230 by a bolt 220, so that both the vane rotor 210 and the camshaft 230 are rotated together. Further, before the vane rotor 210 is fastened to the camshaft 230 by the bolt 220, a space “t” is formed between an outer side wall 213 of the vane rotor 210 and an inner side wall 202 of the housing 200 facing the outer side wall 213.
When the vane rotor 210 is fastened to the camshaft 230 by a bolt 220, a reaction force against a pushing force from a bolt head 222 is operated from the camshaft 230 to the vane rotor 210. If diameter of the bolt head 222 is smaller than diameter of the camshaft 230, diameter of the reaction force from the camshaft 230 is larger than diameter of the pushing force from the bolt head 222. A top portion of the vane rotor 210 is leaned to the inner side wall 202 by a bending moment arisen on the vane rotor 210, so that the outer side wall 213 is formed such a chain double-dashed line shown in FIG. 11. For example, the space between the outer side wall 213 and the inner side wall 202, which is formed in the outside direction of diameter (the top side direction of the vane rotor 210), decreases only 5-20 micro meters or more than from the space “t”. In this case, the vane rotor 210 can not smoothly rotate in the housing 200.
In related art, the space “t” is formed more largely than a preferable space in order to make the vane rotor 210 rotate smoothly, even if the space “t” decreases when the vane rotor 210 and the camshaft 230 are fastened by the bolt 220. For example, the space is formed at 30–80 micro meters.
However, when the vane rotor 210 and the camshaft 230 are fastened by the bolt 220, the space formed in the inside direction of diameter (the down side direction of the vane rotor 210) becomes larger than the preferable space even though the space formed in the outside direction of diameter of that can become the preferable space, so that oil leakage from the housing 200 can increase.